Operations

6.5 Write Cache

Write Cache is the function for reducing the command processing time by separating command control to disk media from write control to disk media. When Write Cache is permitted, the write command can be keep receiving as long as the space available for data transfers remains free on the data buffer. Because of this function, command processing appears to be completed swiftly from the viewpoint of the host. It improves system throughput.

The disk drive has a drive-specific function. When the temperature becomes about -20°C or lower, the function disables the Write cache function, writes data into user areas, and automatically performs the data verify operation (Read check) for those areas. When writing data and verifying the area are completed during this operation, the busy state is canceled. (When the temperature is about -20°C or higher, the disk drive operates depending on whether the SET FEATURES command caching function is enabled or disabled, and only the normal write operation is performed.)

6.5.1 Cache operation

(1) Command that are targets of caching

The Commands that are targets of caching are as follows:

•

•

•

•

•

•

WRITE SECTOR (S)

WRITE MULTIPLE

WRITE DMA

WRITE SECTOR (S) EXT

WRITE MULTIPLE EXT

WRITE DMA EXT

However, the caching operation is not performed when the caching function is prohibited by the SET FEATURES command.

(2) Invalidation of cached data

If an error occurs during writing onto media, write processing is repeated up to as many times as specified for retry processing. If retry fails for a sector because the retry limit is reached, automatic alternate sector processing is executed for the sector. If the automatic alternate sector processing fails, the data in the sector for which automatic alternate sector processing failed is invalidated without being guaranteed.

If data remains in sectors following a sector for which automatic alternate sector processing failed, the data is invalidated without being guaranteed.

Moreover, when the command (clause 6.4.2(3)) is accepted and HOST CRC Error is generated, the caching data is invalidated.

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Fujitsu MHW2060AC manual Write Cache, Cache operation, Command that are targets of caching, Invalidation of cached data
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MHW2060AC, MHW2040AC specifications

The Fujitsu MHW2040AC and MHW2060AC are notable hard disk drives (HDDs) that have been widely used in various computing applications, especially in laptops and compact devices. These models are part of Fujitsu's commitment to providing reliable storage solutions that meet the demands of modern computing.

The MHW2040AC offers a storage capacity of 40 GB, while the MHW2060AC provides a slightly larger capacity at 60 GB. This range of storage makes both models suitable for users looking for dependable space for documents, multimedia files, and software applications. Both drives utilize a 2.5-inch form factor, ideal for mobile computing, as they are lightweight and designed to fit into space-constrained environments.

In terms of performance, both drives operate at a spindle speed of 5400 RPM. This speed strikes a balance between power consumption and performance, making these drives an efficient choice for everyday tasks, such as web browsing and office applications. The drives are equipped with an interface of Ultra ATA/133, which enables faster data transfer rates compared to older models, thereby enhancing overall system responsiveness.

The MHW2040AC and MHW2060AC also incorporate several advanced technologies to bolster their performance and reliability. One such feature is the use of a fluid dynamic bearing (FDB) for the spindle motor, which minimizes noise and vibration, thus improving the overall user experience. Additionally, both drives come with error correction technology that helps maintain data integrity by detecting and correcting errors during read and write operations.

Moreover, these HDDs feature a shock sensor that can detect sudden movements, allowing the drive to park its heads to prevent data loss and hardware damage. This is particularly beneficial in mobile environments where the risks of impact are higher.

Both the MHW2040AC and MHW2060AC are designed with energy-saving features, making them an environmentally responsible choice for energy-conscious consumers. Their low power consumption not only contributes to a reduced carbon footprint but also extends battery life for portable devices.

In summary, the Fujitsu MHW2040AC and MHW2060AC are reliable, efficient, and user-friendly hard disk drives that combine moderate capacities with advanced features designed to enhance performance, ensure data integrity, and extend device longevity. These drives are well-suited for a range of applications, making them a solid choice for users seeking dependable storage solutions.
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